From patchwork Fri Sep 23 19:09:55 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 9348653 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5488E607F2 for ; Fri, 23 Sep 2016 19:10:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3B4502A3C7 for ; Fri, 23 Sep 2016 19:10:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2D9B22AC4E; Fri, 23 Sep 2016 19:10:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from oss.sgi.com (oss.sgi.com [192.48.182.195]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 087312A3C7 for ; Fri, 23 Sep 2016 19:10:09 +0000 (UTC) Received: from oss.sgi.com (localhost [IPv6:::1]) by oss.sgi.com (Postfix) with ESMTP id 078E77CDF; Fri, 23 Sep 2016 14:10:08 -0500 (CDT) X-Original-To: xfs@oss.sgi.com Delivered-To: xfs@oss.sgi.com Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id AF7657CDE for ; Fri, 23 Sep 2016 14:10:03 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay1.corp.sgi.com (Postfix) with ESMTP id 7B9CF8F8040 for ; Fri, 23 Sep 2016 12:10:03 -0700 (PDT) X-ASG-Debug-ID: 1474657798-0bf57b1c5c35630001-NocioJ Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [195.92.253.2]) by cuda.sgi.com with ESMTP id IDX8AJZvX06IivWL (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Fri, 23 Sep 2016 12:09:59 -0700 (PDT) X-Barracuda-Envelope-From: viro@ftp.linux.org.uk X-Barracuda-Effective-Source-IP: zeniv.linux.org.uk[195.92.253.2] X-Barracuda-Apparent-Source-IP: 195.92.253.2 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.86_2 #1 (Red Hat Linux)) id 1bnVr9-0007pR-JM; Fri, 23 Sep 2016 19:09:55 +0000 Date: Fri, 23 Sep 2016 20:09:55 +0100 From: Al Viro To: Linus Torvalds Subject: [PATCH 10/11] new iov_iter flavour: pipe-backed Message-ID: <20160923190955.GH2356@ZenIV.linux.org.uk> X-ASG-Orig-Subj: [PATCH 10/11] new iov_iter flavour: pipe-backed References: <20160909023452.GO2356@ZenIV.linux.org.uk> <20160909221945.GQ2356@ZenIV.linux.org.uk> <20160914031648.GB2356@ZenIV.linux.org.uk> <20160914042559.GC2356@ZenIV.linux.org.uk> <20160917082007.GA6489@ZenIV.linux.org.uk> <20160917190023.GA8039@ZenIV.linux.org.uk> <20160923190032.GA25771@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20160923190032.GA25771@ZenIV.linux.org.uk> User-Agent: Mutt/1.6.1 (2016-04-27) X-Barracuda-Connect: zeniv.linux.org.uk[195.92.253.2] X-Barracuda-Start-Time: 1474657799 X-Barracuda-Encrypted: ECDHE-RSA-AES256-GCM-SHA384 X-Barracuda-URL: https://192.48.176.25:443/cgi-mod/mark.cgi X-Barracuda-Scan-Msg-Size: 19465 X-Virus-Scanned: by bsmtpd at sgi.com X-Barracuda-BRTS-Status: 1 X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=2.7 tests=BSF_SC0_MISMATCH_TO X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.33164 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- 0.00 BSF_SC0_MISMATCH_TO Envelope rcpt doesn't match header Cc: Jens Axboe , CAI Qian , Nick Piggin , xfs@oss.sgi.com, linux-xfs , linux-fsdevel@vger.kernel.org X-BeenThere: xfs@oss.sgi.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com X-Virus-Scanned: ClamAV using ClamSMTP iov_iter variant for passing data into pipe. copy_to_iter() copies data into page(s) it has allocated and stuffs them into the pipe; copy_page_to_iter() stuffs there a reference to the page given to it. Both will try to coalesce if possible. iov_iter_zero() is similar to copy_to_iter(); iov_iter_get_pages() and friends will do as copy_to_iter() would have and return the pages where the data would've been copied. iov_iter_advance() will truncate everything past the spot it has advanced to. New primitive: iov_iter_pipe(), used for initializing those. pipe should be locked all along. Running out of space acts as fault would for iovec-backed ones; in other words, giving it to ->read_iter() may result in short read if the pipe overflows, or -EFAULT if it happens with nothing copied there. In other words, ->read_iter() on those acts pretty much like ->splice_read(). Moreover, all generic_file_splice_read() users, as well as many other ->splice_read() instances can be switched to that scheme - that'll happen in the next commit. Signed-off-by: Al Viro --- [this certainly needs to be documented in more details] fs/splice.c | 2 +- include/linux/splice.h | 1 + include/linux/uio.h | 14 +- lib/iov_iter.c | 390 ++++++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 401 insertions(+), 6 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 085ad37..0daa7d1 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -524,7 +524,7 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, } EXPORT_SYMBOL(generic_file_splice_read); -static const struct pipe_buf_operations default_pipe_buf_ops = { +const struct pipe_buf_operations default_pipe_buf_ops = { .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release, diff --git a/include/linux/splice.h b/include/linux/splice.h index 58b300f..00a2116 100644 --- a/include/linux/splice.h +++ b/include/linux/splice.h @@ -85,4 +85,5 @@ extern void splice_shrink_spd(struct splice_pipe_desc *); extern void spd_release_page(struct splice_pipe_desc *, unsigned int); extern const struct pipe_buf_operations page_cache_pipe_buf_ops; +extern const struct pipe_buf_operations default_pipe_buf_ops; #endif diff --git a/include/linux/uio.h b/include/linux/uio.h index 1b5d1cd..c4fe1ab 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -13,6 +13,7 @@ #include struct page; +struct pipe_inode_info; struct kvec { void *iov_base; /* and that should *never* hold a userland pointer */ @@ -23,6 +24,7 @@ enum { ITER_IOVEC = 0, ITER_KVEC = 2, ITER_BVEC = 4, + ITER_PIPE = 8, }; struct iov_iter { @@ -33,8 +35,12 @@ struct iov_iter { const struct iovec *iov; const struct kvec *kvec; const struct bio_vec *bvec; + struct pipe_inode_info *pipe; + }; + union { + unsigned long nr_segs; + int idx; }; - unsigned long nr_segs; }; /* @@ -64,7 +70,7 @@ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) } #define iov_for_each(iov, iter, start) \ - if (!((start).type & ITER_BVEC)) \ + if (!((start).type & (ITER_BVEC | ITER_PIPE))) \ for (iter = (start); \ (iter).count && \ ((iov = iov_iter_iovec(&(iter))), 1); \ @@ -94,6 +100,8 @@ void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec, unsigned long nr_segs, size_t count); void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec, unsigned long nr_segs, size_t count); +void iov_iter_pipe(struct iov_iter *i, int direction, struct pipe_inode_info *pipe, + size_t count); ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, size_t maxsize, unsigned maxpages, size_t *start); ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, @@ -109,7 +117,7 @@ static inline size_t iov_iter_count(struct iov_iter *i) static inline bool iter_is_iovec(struct iov_iter *i) { - return !(i->type & (ITER_BVEC | ITER_KVEC)); + return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE)); } /* diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 9e8c738..02efc898 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -3,8 +3,11 @@ #include #include #include +#include #include +#define PIPE_PARANOIA /* for now */ + #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ size_t left; \ size_t wanted = n; \ @@ -290,6 +293,82 @@ done: return wanted - bytes; } +#ifdef PIPE_PARANOIA +static bool sanity(const struct iov_iter *i) +{ + struct pipe_inode_info *pipe = i->pipe; + int idx = i->idx; + int delta = (pipe->curbuf + pipe->nrbufs - idx) & (pipe->buffers - 1); + if (i->iov_offset) { + struct pipe_buffer *p; + if (unlikely(delta != 1) || unlikely(!pipe->nrbufs)) + goto Bad; // must be at the last buffer... + + p = &pipe->bufs[idx]; + if (unlikely(p->offset + p->len != i->iov_offset)) + goto Bad; // ... at the end of segment + } else { + if (delta) + goto Bad; // must be right after the last buffer + } + return true; +Bad: + WARN_ON(1); + return false; +} +#else +#define sanity(i) true +#endif + +static inline int next_idx(int idx, struct pipe_inode_info *pipe) +{ + return (idx + 1) & (pipe->buffers - 1); +} + +static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, + struct iov_iter *i) +{ + struct pipe_inode_info *pipe = i->pipe; + struct pipe_buffer *buf; + size_t off; + int idx; + + if (unlikely(bytes > i->count)) + bytes = i->count; + + if (unlikely(!bytes)) + return 0; + + if (!sanity(i)) + return 0; + + off = i->iov_offset; + idx = i->idx; + buf = &pipe->bufs[idx]; + if (off) { + if (offset == off && buf->page == page) { + /* merge with the last one */ + buf->len += bytes; + i->iov_offset += bytes; + goto out; + } + idx = next_idx(idx, pipe); + buf = &pipe->bufs[idx]; + } + if (idx == pipe->curbuf && pipe->nrbufs) + return 0; + pipe->nrbufs++; + buf->ops = &page_cache_pipe_buf_ops; + get_page(buf->page = page); + buf->offset = offset; + buf->len = bytes; + i->iov_offset = offset + bytes; + i->idx = idx; +out: + i->count -= bytes; + return bytes; +} + /* * Fault in the first iovec of the given iov_iter, to a maximum length * of bytes. Returns 0 on success, or non-zero if the memory could not be @@ -376,9 +455,98 @@ static void memzero_page(struct page *page, size_t offset, size_t len) kunmap_atomic(addr); } +static inline bool allocated(struct pipe_buffer *buf) +{ + return buf->ops == &default_pipe_buf_ops; +} + +static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp) +{ + size_t off = i->iov_offset; + int idx = i->idx; + if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) { + idx = next_idx(idx, i->pipe); + off = 0; + } + *idxp = idx; + *offp = off; +} + +static size_t push_pipe(struct iov_iter *i, size_t size, + int *idxp, size_t *offp) +{ + struct pipe_inode_info *pipe = i->pipe; + size_t off; + int idx; + ssize_t left; + + if (unlikely(size > i->count)) + size = i->count; + if (unlikely(!size)) + return 0; + + left = size; + data_start(i, &idx, &off); + *idxp = idx; + *offp = off; + if (off) { + left -= PAGE_SIZE - off; + if (left <= 0) { + pipe->bufs[idx].len += size; + return size; + } + pipe->bufs[idx].len = PAGE_SIZE; + idx = next_idx(idx, pipe); + } + while (idx != pipe->curbuf || !pipe->nrbufs) { + struct page *page = alloc_page(GFP_USER); + if (!page) + break; + pipe->nrbufs++; + pipe->bufs[idx].ops = &default_pipe_buf_ops; + pipe->bufs[idx].page = page; + pipe->bufs[idx].offset = 0; + if (left <= PAGE_SIZE) { + pipe->bufs[idx].len = left; + return size; + } + pipe->bufs[idx].len = PAGE_SIZE; + left -= PAGE_SIZE; + idx = next_idx(idx, pipe); + } + return size - left; +} + +static size_t copy_pipe_to_iter(const void *addr, size_t bytes, + struct iov_iter *i) +{ + struct pipe_inode_info *pipe = i->pipe; + size_t n, off; + int idx; + + if (!sanity(i)) + return 0; + + bytes = n = push_pipe(i, bytes, &idx, &off); + if (unlikely(!n)) + return 0; + for ( ; n; idx = next_idx(idx, pipe), off = 0) { + size_t chunk = min_t(size_t, n, PAGE_SIZE - off); + memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk); + i->idx = idx; + i->iov_offset = off + chunk; + n -= chunk; + addr += chunk; + } + i->count -= bytes; + return bytes; +} + size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { const char *from = addr; + if (unlikely(i->type & ITER_PIPE)) + return copy_pipe_to_iter(addr, bytes, i); iterate_and_advance(i, bytes, v, __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), @@ -394,6 +562,10 @@ EXPORT_SYMBOL(copy_to_iter); size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) { char *to = addr; + if (unlikely(i->type & ITER_PIPE)) { + WARN_ON(1); + return 0; + } iterate_and_advance(i, bytes, v, __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), @@ -409,6 +581,10 @@ EXPORT_SYMBOL(copy_from_iter); size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) { char *to = addr; + if (unlikely(i->type & ITER_PIPE)) { + WARN_ON(1); + return 0; + } iterate_and_advance(i, bytes, v, __copy_from_user_nocache((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), @@ -429,14 +605,20 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, size_t wanted = copy_to_iter(kaddr + offset, bytes, i); kunmap_atomic(kaddr); return wanted; - } else + } else if (likely(!(i->type & ITER_PIPE))) return copy_page_to_iter_iovec(page, offset, bytes, i); + else + return copy_page_to_iter_pipe(page, offset, bytes, i); } EXPORT_SYMBOL(copy_page_to_iter); size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { + if (unlikely(i->type & ITER_PIPE)) { + WARN_ON(1); + return 0; + } if (i->type & (ITER_BVEC|ITER_KVEC)) { void *kaddr = kmap_atomic(page); size_t wanted = copy_from_iter(kaddr + offset, bytes, i); @@ -447,8 +629,34 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, } EXPORT_SYMBOL(copy_page_from_iter); +static size_t pipe_zero(size_t bytes, struct iov_iter *i) +{ + struct pipe_inode_info *pipe = i->pipe; + size_t n, off; + int idx; + + if (!sanity(i)) + return 0; + + bytes = n = push_pipe(i, bytes, &idx, &off); + if (unlikely(!n)) + return 0; + + for ( ; n; idx = next_idx(idx, pipe), off = 0) { + size_t chunk = min_t(size_t, n, PAGE_SIZE - off); + memzero_page(pipe->bufs[idx].page, off, chunk); + i->idx = idx; + i->iov_offset = off + chunk; + n -= chunk; + } + i->count -= bytes; + return bytes; +} + size_t iov_iter_zero(size_t bytes, struct iov_iter *i) { + if (unlikely(i->type & ITER_PIPE)) + return pipe_zero(bytes, i); iterate_and_advance(i, bytes, v, __clear_user(v.iov_base, v.iov_len), memzero_page(v.bv_page, v.bv_offset, v.bv_len), @@ -463,6 +671,11 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes) { char *kaddr = kmap_atomic(page), *p = kaddr + offset; + if (unlikely(i->type & ITER_PIPE)) { + kunmap_atomic(kaddr); + WARN_ON(1); + return 0; + } iterate_all_kinds(i, bytes, v, __copy_from_user_inatomic((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), @@ -475,8 +688,55 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, } EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); +static void pipe_advance(struct iov_iter *i, size_t size) +{ + struct pipe_inode_info *pipe = i->pipe; + struct pipe_buffer *buf; + size_t off; + int idx; + + if (unlikely(i->count < size)) + size = i->count; + + idx = i->idx; + off = i->iov_offset; + if (size || off) { + /* take it relative to the beginning of buffer */ + size += off - pipe->bufs[idx].offset; + while (1) { + buf = &pipe->bufs[idx]; + if (size > buf->len) { + size -= buf->len; + idx = next_idx(idx, pipe); + off = 0; + } else { + buf->len = size; + i->idx = idx; + i->iov_offset = off = buf->offset + size; + break; + } + } + idx = next_idx(idx, pipe); + } + if (pipe->nrbufs) { + int unused = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); + /* [curbuf,unused) is in use. Free [idx,unused) */ + while (idx != unused) { + buf = &pipe->bufs[idx]; + buf->ops->release(pipe, buf); + buf->ops = NULL; + idx = next_idx(idx, pipe); + pipe->nrbufs--; + } + } +} + void iov_iter_advance(struct iov_iter *i, size_t size) { + if (unlikely(i->type & ITER_PIPE)) { + pipe_advance(i, size); + return; + } iterate_and_advance(i, size, v, 0, 0, 0) } EXPORT_SYMBOL(iov_iter_advance); @@ -486,6 +746,8 @@ EXPORT_SYMBOL(iov_iter_advance); */ size_t iov_iter_single_seg_count(const struct iov_iter *i) { + if (unlikely(i->type & ITER_PIPE)) + return i->count; // it is a silly place, anyway if (i->nr_segs == 1) return i->count; else if (i->type & ITER_BVEC) @@ -521,6 +783,19 @@ void iov_iter_bvec(struct iov_iter *i, int direction, } EXPORT_SYMBOL(iov_iter_bvec); +void iov_iter_pipe(struct iov_iter *i, int direction, + struct pipe_inode_info *pipe, + size_t count) +{ + BUG_ON(direction != ITER_PIPE); + i->type = direction; + i->pipe = pipe; + i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); + i->iov_offset = 0; + i->count = count; +} +EXPORT_SYMBOL(iov_iter_pipe); + unsigned long iov_iter_alignment(const struct iov_iter *i) { unsigned long res = 0; @@ -529,6 +804,11 @@ unsigned long iov_iter_alignment(const struct iov_iter *i) if (!size) return 0; + if (unlikely(i->type & ITER_PIPE)) { + if (i->iov_offset && allocated(&i->pipe->bufs[i->idx])) + return size | i->iov_offset; + return size; + } iterate_all_kinds(i, size, v, (res |= (unsigned long)v.iov_base | v.iov_len, 0), res |= v.bv_offset | v.bv_len, @@ -545,6 +825,11 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i) if (!size) return 0; + if (unlikely(i->type & ITER_PIPE)) { + WARN_ON(1); + return ~0U; + } + iterate_all_kinds(i, size, v, (res |= (!res ? 0 : (unsigned long)v.iov_base) | (size != v.iov_len ? size : 0), 0), @@ -557,6 +842,47 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i) } EXPORT_SYMBOL(iov_iter_gap_alignment); +static inline size_t __pipe_get_pages(struct iov_iter *i, + size_t maxsize, + struct page **pages, + int idx, + size_t *start) +{ + struct pipe_inode_info *pipe = i->pipe; + size_t n = push_pipe(i, maxsize, &idx, start); + if (!n) + return 0; + + maxsize = n; + n += *start; + while (n >= PAGE_SIZE) { + *pages++ = pipe->bufs[idx].page; + idx = next_idx(idx, pipe); + n -= PAGE_SIZE; + } + + return maxsize; +} + +static ssize_t pipe_get_pages(struct iov_iter *i, + struct page **pages, size_t maxsize, unsigned maxpages, + size_t *start) +{ + unsigned npages; + size_t capacity; + int idx; + + if (!sanity(i)) + return 0; + + data_start(i, &idx, start); + /* some of this one + all after this one */ + npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; + capacity = min(npages,maxpages) * PAGE_SIZE - *start; + + return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start); +} + ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, size_t maxsize, unsigned maxpages, size_t *start) @@ -567,6 +893,8 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, if (!maxsize) return 0; + if (unlikely(i->type & ITER_PIPE)) + return pipe_get_pages(i, pages, maxsize, maxpages, start); iterate_all_kinds(i, maxsize, v, ({ unsigned long addr = (unsigned long)v.iov_base; size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); @@ -602,6 +930,37 @@ static struct page **get_pages_array(size_t n) return p; } +static ssize_t pipe_get_pages_alloc(struct iov_iter *i, + struct page ***pages, size_t maxsize, + size_t *start) +{ + struct page **p; + size_t n; + int idx; + int npages; + + if (!sanity(i)) + return 0; + + data_start(i, &idx, start); + /* some of this one + all after this one */ + npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; + n = npages * PAGE_SIZE - *start; + if (maxsize > n) + maxsize = n; + else + npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); + p = get_pages_array(npages); + if (!p) + return -ENOMEM; + n = __pipe_get_pages(i, maxsize, p, idx, start); + if (n) + *pages = p; + else + kvfree(p); + return n; +} + ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, size_t maxsize, size_t *start) @@ -614,6 +973,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, if (!maxsize) return 0; + if (unlikely(i->type & ITER_PIPE)) + return pipe_get_pages_alloc(i, pages, maxsize, start); iterate_all_kinds(i, maxsize, v, ({ unsigned long addr = (unsigned long)v.iov_base; size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); @@ -655,6 +1016,10 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, __wsum sum, next; size_t off = 0; sum = *csum; + if (unlikely(i->type & ITER_PIPE)) { + WARN_ON(1); + return 0; + } iterate_and_advance(i, bytes, v, ({ int err = 0; next = csum_and_copy_from_user(v.iov_base, @@ -693,6 +1058,10 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, __wsum sum, next; size_t off = 0; sum = *csum; + if (unlikely(i->type & ITER_PIPE)) { + WARN_ON(1); /* for now */ + return 0; + } iterate_and_advance(i, bytes, v, ({ int err = 0; next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, @@ -732,7 +1101,20 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages) if (!size) return 0; - iterate_all_kinds(i, size, v, ({ + if (unlikely(i->type & ITER_PIPE)) { + struct pipe_inode_info *pipe = i->pipe; + size_t off; + int idx; + + if (!sanity(i)) + return 0; + + data_start(i, &idx, &off); + /* some of this one + all after this one */ + npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1; + if (npages >= maxpages) + return maxpages; + } else iterate_all_kinds(i, size, v, ({ unsigned long p = (unsigned long)v.iov_base; npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) - p / PAGE_SIZE; @@ -757,6 +1139,10 @@ EXPORT_SYMBOL(iov_iter_npages); const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) { *new = *old; + if (unlikely(new->type & ITER_PIPE)) { + WARN_ON(1); + return NULL; + } if (new->type & ITER_BVEC) return new->bvec = kmemdup(new->bvec, new->nr_segs * sizeof(struct bio_vec),